Crystals of superconducting ${\mathrm{Mo}}_8{\mathrm{Ga}}_{41}$ $\left(T_c=9.8\mathrm{K}\right)$ and ${\mathrm{Mo}}_{8-x}{\mathrm{V}}_x{\mathrm{Ga}}_{41}$ limited solid solution $[x_{\max }=1.9\left(2\right)]$ have been grown from the high-temperature Ga flux and confirmed to have the ${\mathrm{V}}_8{\mathrm{Ga}}_{41}$ type of crystal structure at room temperature. Thermodynamic and transport measurements as well as electronic structure calculations were performed to investigate both normal- and superconducting-state properties of ${\mathrm{Mo}}_8{\mathrm{Ga}}_{41}$. The discontinuity in the heat capacity at $T_c, \mathrm{\Delta }{c}_p/{\gamma }_N{T}_c=2.83$ in zero magnetic field, indicates a much stronger electron-phonon coupling than in the standard BCS limit. From the heat-capacity data, we estimated the electron-phonon coupling constant ${\lambda }_{ep}=0.9$. The upper critical field is ${\mu }_0{H}_{c2}\left(0\right)=8.3\mathrm{T}$, while the lower one is only ${\mu }_0{H}_{c1}\left(0\right)=131\mathrm{Oe}$. The upper critical field of ${\mathrm{Mo}}_8{\mathrm{Ga}}_{41}$ exhibits a clear enhancement with respect to the Werthamer-Helfand-Honenberg prediction, consistent with the strong electron-phonon coupling. The ${\mathrm{Mo}}_{8-x}{\mathrm{V}}_x{\mathrm{Ga}}_{41}$ limited solid solution also exhibits superconducting properties, and the critical temperature $T_c$ is reduced only slightly with increasing $x$.

Zero-field and transverse-field muon spin rotation/relaxation ($\mu \mathrm{SR}$) experiments were undertaken in order to elucidate the microscopic properties of a strongly coupled superconductor ${\mathrm{Mo}}_8{\mathrm{Ga}}_{41}$ with $T_{\text{c}}=9.8$ K. The upper critical field extracted from the transverse-field $\mu \mathrm{SR}$ data exhibits significant reduction with respect to the data from thermodynamic measurements indicating the coexistence of two independent length scales in the superconducting state. Accordingly, the temperature-dependent magnetic penetration depth of ${\mathrm{Mo}}_8{\mathrm{Ga}}_{41}$ is described using a model in which two $s$ wave superconducting gaps are assumed. A V for Mo substitution in the parent compound leads to the complete suppression of one superconducting gap, and ${\mathrm{Mo}}_7{\mathrm{VGa}}_{41}$ is well described within the single $s$ wave gap scenario. The reduction in the superfluid density and the evolution of the low-temperature resistivity upon V substitution indicate the emergence of a competing state in ${\mathrm{Mo}}_7{\mathrm{VGa}}_{41}$ that may be responsible for the closure of one of the superconducting gaps.

Synthesis, thermodynamic properties, and microscopic magnetic model of ilinskite-type KCu₅O₂(SeO₃)₂Cl₃ built by corner-sharing Cu₄ tetrahedra are reported, and relevant magnetostructural correlations are discussed. Quasi-one-dimensional magnetic behavior with the short-range order around 50 K is rationalized in terms of weakly coupled spin ladders (tubes) having a complex topology formed upon fragmentation of the tetrahedral network. This fragmentation is rooted in the non-trivial effect of the SeO₃ groups that render the Cu–O–Cu superexchange strongly ferromagnetic even at bridging angles exceeding 110°.

In previous decades, investigation of superconductors was aimed either at finding materials with higher critical temperatures or at discovering nontypical superconducting behavior. Here, we present the cupric (CuO) thin films, which were synthesized by atomic layer deposition by using a metal-organic precursor, copper (II)-bis-(-dimethylamino-2-propoxide), and ozone as an oxidizer. The deposition process was optimized by employing a quartz crystal monitoring, and the contact between the deposited films and planar and three-dimensional SiO₂/Si substrates was examined by scanning electron microscopy with a focused ion beam module. Phase and elemental composition were analyzed by X-ray diffraction and X-ray fluorescence. Two-probe electrical resistivity measurements revealed a resistivity drop below the critical temperature of 4 K, which may indicate low-temperature superconductivity of the CuO thin films.